KR20000037279A - External Electrode-Type Fluorescent Lamp for the LCD Back-Light - Google Patents

Abstract

PURPOSE: An outer tube type fluorescent lamp for liquid crystal display backlight is provided to remove inner electrode out of a cylindrical fluorescent lamp. CONSTITUTION: An outer tube type fluorescent lamp for liquid crystal display backlight includes a cylindrical fluorescent tube(1) and a conductive material. The conductive material is applied on both ends of the cylindrical fluorescent tube(1), or a conductive capsule is covered on the cylindrical fluorescent plate. The outer tube type fluorescent lamp for liquid crystal display backlight is activated by alternating power. One or plurality of fluorescent plates is or are further arranged on a plane to form the outer tube type fluorescent lamp for liquid crystal display backlight. The shape of the fluorescent plate is further manufactured as a planar plate.

Description

External Electrode-Type Fluorescent Lamp for the LCD Back-Light}

The present invention is a fluorescent tube designed primarily for use in LCD-backlight, and can also be used as an illumination lamp. LCD monitor backlights for notebook computers and PCs require high brightness flat light sources. The present invention is to arrange a plurality of cylindrical fluorescent tubes in a plane or to use a flat fluorescent tube as a backlight. The present invention is characterized in that no electrode is provided inside the fluorescent tube. The electrode is a method of producing a plasma by discharging a fluorescent tube by applying a metal to a predetermined region of both ends of the outside of the tube and connected to a power source. Fluorescent lamps manufactured in this way are arranged in planes and connected in parallel to the power supply. At this time, by adopting the voltage and frequency of the AC power supply properly, a flat light source with high brightness and high efficiency is made. The present invention has been designed for the purpose of connecting a plurality of fluorescent tubes by the AC discharge in parallel to the power supply by installing the electrode outside the fluorescent tube.

Conventional LCD backlighters include a direct type method and a light guide plate method. The direct type arranges a plurality of fluorescent lamps in the plane. In the direct type, since the shape of the fluorescent lamp appears on the liquid crystal panel, the gap between the lamp and the liquid crystal panel should be kept considerably. Therefore, the direct type has a limitation in thinning, and there is a problem in the uniformity of the overall brightness of the panel. Therefore, a plurality of fluorescent lamps should be installed to minimize the gap between the fluorescent lamps for thinning. When a plurality of such fluorescent lamps are connected in parallel to the power source, only a few lamps emit light, and emission luminances are also different. As a result, many fluorescent lamps cannot be connected to the power supply in parallel. Since the voltage must be applied separately, the number and size of inverters for power supply are problematic. Therefore, there is a limit to the number of fluorescent tubes in arranging multiple fluorescent tubes. In the case of employing a linear electrode in a flat fluorescent tube, plasma is not evenly generated throughout the plane.

Conventional fluorescent lamps are equipped with hot cathode or cold cathode electrodes at both ends of the fluorescent tube, and are connected to an AC power source to generate plasma, and a DC real current flows through the electrodes. As such, the process of installing the electrode inside the fluorescent tube is difficult and also causes a problem in the life of the fluorescent lamp. In particular, when a plurality of fluorescent lamps are installed in a plane, the light emission luminance of each lamp is different, and it is difficult to adjust the luminance of each fluorescent lamp. In the case of flat lamps, since plasma is generated locally by discharge, it is difficult to realize uniform luminance in the entire plane. As a result, it is difficult to implement a high luminance and high efficiency planar light source with uniform luminance, and thus it is difficult to be used as a backlight for an LCD for a monitor.

The present invention basically removes an internal electrode from a cylindrical fluorescent lamp having an inner diameter of about 2 mm, which is conventionally used as an LCD backlight. The phosphor is simply applied to a cylindrical glass tube and sealed by injecting gas for discharging. The electrode is coated with a metal surface of a certain portion of the outer wall of both ends of the glass tube. Since there is no process to install electrodes in the tube, production costs are low and there is no problem of lamp life due to electrode damage. Therefore, there is no technical problem in production.

By arranging a plurality of cylindrical lamps on a plane and connecting them in parallel to the power supply, a method of adjusting the spacing between the lamps to have a uniform brightness and installing a light guide plate between the lamps may be used.

Similar to the luminance of a cylindrical lamp with an inner diameter of 2 mm of the DC discharge used in a conventional LCD backlight, the frequency and the frequency of the same lamp (gas injection and the same phosphor) of the same lamp provided with the external electrode in the present invention are installed. The luminous efficiency is increased with the luminance of 10,000 cd / m 2 or more depending on the applied voltage. In addition, as a result of connecting a plurality of external electrode lamps in parallel to the same power source it was confirmed that all the lamps emit the same brightness. Therefore, there is no technical problem other than optimization of the voltage and frequency of the inverter, the electrode area, and the pressure according to the type of discharge gas.

Meanwhile, in the present invention, when the cylindrical lamps are disposed on a flat surface for use as the LDC backlight, optimization of the shape of the light guide plate provided between the lamps and the lamps is required. In the case of directly manufacturing the shape of the lamp plate, the production of sheet metal for molding the glass is an important problem.

FIG. 1 is a cross-sectional view of a cylindrical fluorescent tube in a cylindrical longitudinal direction in which there is no electrode inside a fluorescent tube and an electrode is coated on an outer glass surface at both ends of the fluorescent tube.

FIG. 2 is a conceptual diagram of an LCD backlighting apparatus in which an external tube cylindrical lamp is disposed in a plane and multiple fluorescent tubes are applied to a power source in a parallel connection manner, and the arrangement of multiple fluorescent tubes (a) and a mixed arrangement of fluorescent tubes and light guide plates (b) ) And a mixed method (c) in which a fluorescent lamp is installed inside the light guide plate.

3 is a flat lamp for LCD-backlighter in which an alternating current flows in a tube by bending an elongated cylindrical microfluorescence tube having no electrode in the tube and placing it on a plane and applying electrodes to outer glass surfaces at both ends. Conceptual diagram of the method (a) and the light guide plate mixing method (b).

4 is a conceptual view (a) of the fluorescent plate structure of the upper plate and the lower plate produced by the glass molding method as a thin extra-electrode flat plate lamp (b) and the assembled cross-sectional view (b).

Reference numerals of the main parts of the drawings are as follows.

One; Fluorescent tube 2; Fluorescent layer 3; Extra electrodes, 4; Parallel connection terminal, 5; Reflector 6; Diffusion film, 7; Light guide plate, 8; A light guide plate inner groove, 9; Top glass, 10; Bottom glass, 11; Discharge tube, 12; Glass bulkhead, 13, gas passage.

The present invention is a fluorescent tube or fluorescent plate for a high-brightness LCD-lighter of a large liquid crystal display (LCD) device, which has no electrode inside the fluorescent tube and installs an electrode on an external glass surface so that an alternating current flows in the tube. Fluorescent lamp of the type. It is also an invention of their arrangement and geometry for using these lamps as backlights. As in the conventional direct type method, a plurality of fluorescent lamps are arranged in a plane or a light guide plate is provided between the lamps, and is designed for a thin back lighter for the purpose of uniform luminance by scattering of light together with a reflecting plate.

1 is a conceptual diagram showing a cylindrical fluorescent tube 1 and electrodes applied to outer surfaces of both ends. Conventional cylindrical fluorescent lamps are provided with electrodes of a hot cathode or a cold cathode inside both ends. However, in the present invention, the electrode is not provided inside the fluorescent tube, and both ends of the tube are covered with a conductor. That is, in the conventional fluorescent tube, the internal electrode is removed, and the fluorescent layer 2 is simply formed on the inner wall of the glass tube, and a discharge gas is injected and sealed. In order to discharge the fluorescent tube, a so-called extra-tube electrode 3 is provided on both outer glass surfaces of the fluorescent tube as shown in FIG. 1. The electrode can be installed by applying conductors by immersing both ends in a metal solution, by attaching a metal tape, and by applying a metal capsule. As the metal, a material having a small electric resistance such as aluminum, silver, or copper is used. In addition, an insulator may be additionally applied except for a portion connected to a power source. The area of the electrode to be applied is related to the discharge current. In consideration of the desired brightness and efficiency, it is installed in an optimal area. The inside of the fluorescent tube is the same as the coating method of the conventional fluorescent layer 2. However, a dielectric may be applied to the glass surfaces at both ends of the inside of the tube to which the electrode is applied for the purpose of increasing the long life and the generation of secondary electrons. In this case, the dielectric used may be MgO, CaO, or the like, which may serve as a protective film. As the discharge gas inside the fluorescent tube, a mixture of inert gas, mercury, and the like are injected as in the prior art.

The cross section of the fluorescent tube is in addition to the cylindrical shape as shown in FIG. 1, and may have various shapes such as a rectangle, a triangle, an ellipse, and the like. Both of these apply the extra-electrode 3 to the glass surface at both ends.

FIG. 2 is a conceptual view of a backlighter in which a cylindrical lamp as shown in FIG. 1 is arranged in a plane. It consists of a fluorescent tube (1), a reflecting plate (5), and a diffusion film (6). The direct type (a) and the mixed type (b-c) using the light guide plate are shown. The connection method (4) to the power supply of the electrode shown in the figure is parallel connection as described above, and uniform brightness is possible for each lamp. FIG. 2 (a) shows a direct arrangement, aiming for uniform brightness by minimizing the distance between lamps. Optimize the spacing of the lamps and the height between the diffuser film 6 and the fluorescent tube. Reducing the spacing of lamps for thin flat plates increases the number of lamps. 2 (b) and 2 (c) are intended to reduce the number of fluorescent tubes by mixing a lamp and a light guide plate 7 designed for uniform luminance. The light guide plate is designed to have a uniform brightness as used in a conventional LCD backlight. FIG. 2 (b) shows a light guide plate between the lamps at regular intervals, and FIG. 2 (c) shows a method of installing a lamp by making a groove 8 in the light guide plate.

Figure 3 is to be used as a flat panel backlight by bending an elongated microfluorescence tube to a constant length. Applying the extra-electrode electrode 3 to the ends of both ends by connecting to the power source has the effect of connecting the respective fluorescent tubes in parallel. For the purpose of uniform brightness on the plane, only the fluorescent tube may be arranged as shown in FIG. 3A or a light guide plate may be provided between the fluorescent tubes as shown in FIG.

4 is designed to have a glass plate formed in a cast form to have the effect of installing the multiple cylinder form inside the glass plate (a-b). The upper plate 9 and the lower plate 10 are manufactured to apply phosphors, and the upper and lower plates a are attached thereto. Such a plate type may adopt various shapes in addition to the cylindrical cross-sectional shape as shown in FIG. 4B for multiple discharge spaces. In order to form the individual discharge tubes 11 and to support the space between the upper plate and the lower plate, a glass partition 12 structure is provided. At this time, the gas passage 13 is provided in the middle portion so that the gas can communicate between the discharge tubes (11).

The use of LCDs as display devices replacing CRTs is being expanded. The trend is expanding from notebook PCs to desktop monitors and LCD TVs. Therefore, the size of the backlight is also increasing in demand for large screens of 10 inches to 20 inches or more. At the same time, high brightness and high efficiency are required. In this respect, the proposed backlight writer has the characteristics of the highest brightness and high efficiency of existing individual fluorescent lamps. Therefore, since the brightness of the backlight is not a limiting factor for the LCD of the large screen, it will bring a big change in the LCD technology enhancement and market expansion.

Claims (3)

An external tube fluorescent lamp driven by an alternating current power source having a structure in which an electrode is formed in such a manner as to apply a conductive material or cover a conductive capsule to both surfaces of a cylindrical fluorescent tube. One or a plurality of fluorescent tubes having an extra-electrode electrode of the form as described in claim 1 on the plane, or the fluorescent tube itself is produced in the form of a flat type fluorescent lamp used as a surface light emitting source. A flat fluorescent lamp comprising a light guide plate disposed between the fluorescent tubes as described in claim 1 or a groove formed in the light guide plate.